Radio antenna



, Ju31e13, 1933.

(-7 0 OWISldE Groundnsi.

I. O. BANKS RADIO ANTENNA Filed Aug. 22, 1930 a Set Anierma R75? 6T0 Sef Gmund Post Ira Q 2321M Jmmtoz Patented June 13, 1933 IRA O.

BANKS, O1? HIGGINSVILLE, MISSOURI, ASSIGNOR OF ONE-HALF T IAUL R.

HEIDBRI'NK, OF HIGGINSVILLE, MISSOURI RADIO ANTENNA Application filed August 22, 1930. Serial No. 477,155.

This invention relates to radio antenna and an object of the invention is to devise a radio antenna which may be housed within a radio with means for effectively controlling 5 the length of the antenna to vary the effective volume and tone of the radio.

Referring to the accompanying drawing which is made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a plan view of the devlce,

Figure 2, a view of the interior of the casing looking in the opposite direction from that seen in Figure 1, and c Figure 3, a diagrammatic view of the device.

In the drawing numeral 10 indicates a casing in which the elements are housed. Secured within the casing are posts 11, 12 and 13 which are connected by Wires to the radio set antenna post, to the ground post on the set and to the outside ground post respectively. Post 12 is connected by means of a wire it to a post 21 on which an arm 22 is pivoted, the arm carrying a roller 23 on its outer end for engaging with the resistance element 19 which is built in the form of a coil. One end of the resistance 19 is connected by means of wire 15 with the binding post 13 and the other end of the resistance is connected by means of a wire 17 with a condenser 18. The wire 15 and the condenser 18 are connected by wires 16 and 20 respectively with the antenna post 11. The arm 22 is operated by means of a knob 24 which is connected to the post 21.

In operation the antenna is connected to the radio set as described and as indicated in Figure 3 when the operator wishes to control the length of the antenna he may operate the knob 24 to bring the roller 28 into contact with the antenna 19 at any point desired so as to eliminate as much of the aerial a as he chooses. By thus manipulating the dial or knob 2A he may selectively use any length of aerial which he chooses. This gives a wide range of selectivity which is particularly desirable when shifting from stations at greater or less distance from his set. By varying the length of his antenna he may get a volume and tone control which is impossible with an aerial of a constant length. l/Vith a selectivity of say from zero or a few feet up to a maximum of 100 feet or more the operator is able to effectively control the amount of current received by the set. This adjustment, of course, may be instantly made so as to give the operator complete and ready control over the length of his antenna. While the device is not primarily a static eliminator it does give the operator some control over the amount of static in the machine since it enables him to cut down the length of the exposed aerial.

It Will be obvious to those skilled in the art that various changes may be made in my device without departing from the spirit of the invention and therefore I do not limit myself to what is shown in the drawing and described in the specification, but only as indicated in the appended claim.

Having thus fully described my said invention, what I claim as new and desire to secure by Letters Patent, is

An antenna for a radio set comprising a casing having binding posts thereon, the first of said posts being connectedrto a wire leading to the radio set antenna post, a second having a wire leading to the ground post on the set and a third connected to a wire attached to an outside ground post, the second of said posts being connected in circuit with a fourth post, a movable arm pivotally attached to the last named post, a roller carried by the outer end of said arm, a resistance coil having one end connected to the said third post andhaving its other end connected through a con-- denser with the said first post, said roller being inrengagement with the said coil, substantially as set forth. 90

In Witness whereof, I have hereunto set my hand at Higginsville, Missouri this 16th day of August, A. D. nineteen hundred and thirty.

IRA O. BANKS. 

